1. Technical Field
The present invention relates to a light source module and more particularly, the present invention relates to a light source module and a display apparatus having the light source module.
2. Discussion of the Related Art
Generally, a liquid crystal display (LCD) apparatus includes a backlight assembly providing light to a display panel to display an image. A cold cathode fluorescent lamp (CCFL) is often used as a light source of the backlight assembly. More recently, light-emitting diodes (LEDs) have been used as a light source because the LED has low power consumption, small volume and light weight.
One challenge in using LEDs as a backlight light source is to produce a white light, as LEDs tend to be monochromatic. One approach to creating white light from LEDs is to coat a blue LED chip with a yellow fluorescent material. However, the above-mentioned blue LED chip merely uses blue and yellow light to emit the white light without using full colors having red, green and blue light, and thus color reproducibility of the display panel is decreased.
Research has been conducted to enhance color reproducibility in LED backlights, but a light source having good color reproducibility and good light efficiency has not been easy to develop. For example, emitting white light by mixing red, green and blue LEDs is the most reliable method for producing good color reproducibility and good light efficiency. However, the degree of light output from LEDs may be highly dependent on temperature, with each color LED having a different temperature response. Accordingly, in order to create an even white light, driving conditions for the LEDs may be changed to account for a relatively low temperature at activation. “Color coordinates” relates to an approach for representing the appearance of a color in terms of a set of numeric values for each of the constituent primary colors. Color coordinates may represent a color as a set of three numbers, for example, a red value between 0 and 255, a green value between 0 and 255, and a blue value between 0 and 255. Alternatively, color coordinates may be expressed as a set of percentages, degrees or other values. Thus, color coordinates indicates a value for the color being displayed. One example of a popularly used color coordinate system is the Adobe color coordinate system. Because temperature can affect a red, blue and green LED differently, changes in temperature may result in undesirable changes in color coordinates.
Thus, to prevent the changing of the color coordinates, a feedback system using a color sensor has been developed, but to increase the sensitivity of the color sensor, to realize an optical system having optimal color sensing ability, and to increase the quality of color compensation, sophisticated logic is used. In addition, the number of LEDs used and costs due to the feedback system may be relatively high.